<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

<script>
    // concat 拼接
    // join 更换连接符号，转换为字符串
    // slice 选取
    // splice 删除

    var obj = {
        0: 'a',
        1: 'b',
        2: 'c',
        length: 3
    }

    var str = 'this is my test text'

    console.log(str.slice(0, 6))

    console.log(str.length)

    console.log(Array.from(obj))
    console.log(Array.from(str))
</script>

</body>
</html>